Neither of them were difficult for me. They are both equal in my opinion. I'm not going to lie and say I beat either of them on my first and second try however. I know all of KH1's Sephiroth's tatics, its impossible for me to EVER lose that battle again. KH2's Sephiroth, unlike KH1's, was unpredictable. This made the fight somewhat more difficult than KH1's. BUT, KH1's Sephiroth, unlike KH2's Sephiroth, was NOT NEARLY as vunerable. Seriously, can you complete 3 combos in a row on KH1's Sephiroth, you'd be lucky if you finished 1! With those to traits, I think that evenly balances the two out. But, I don't know about the rest of you.